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Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
The task is not correct.
"and returns true only if the function in the params returns true for exactly one (1) item in the sequence."
The function can return something like "yes" and you should see at as True, otherwhise some tests fail.